1968

6.0

2002

6.2

2004

6.3

2006

6.7

2007

5.8

2000

6.1

2007

6.3

1959

6.3

1982

5.6

1946

5.3

2000

5.8

1994

6.4

1959

5.1

1931

6.8

1980

6.8

1996

7.0

2000

5.5

2004

7.3

1964

7.5

2002

6.5